The best timing, tips and workouts for outdoor exercise in extreme heat

Considering that temperatures routinely exceed 42°C in North India, one can understand the urge to avoid outdoor exercise in the summer months. Nevertheless, with a certain degree of preparation and adaptation, it can be done safely. It is important to understand how the body responds to extreme conditions and what measures are needed.

The effect of heat on an active body

During physical activity, a lot of heat is generated by muscle metabolism. Under normal conditions, the body easily copes with its release through sweating and increased blood flow to the skin. Extreme heat creates serious challenges for a person. The cardiovascular system should deliver blood both to working muscles and the skin for cooling. This means increasing the heart rate and reducing endurance, which, in turn, may lead to heat exhaustion or even a fatal condition called heat stroke.

When the body temperature exceeds 40°C, the brain stops functioning normally. When it rises further to 41°C, proteins in the body’s cells can get damaged. All of these effects can be experienced in just 30 to 60 minutes of intense physical activity at 43°C.

The timing window

There is one best practice that involves working out. The sun and heat are at their highest points between 11 AM and 4 PM. This period must not be used for any outdoor physical activity during the peak summer months. The best time periods are early mornings between 5:30 and 7:30 AM and late afternoons and evenings after 6:30 PM, when surface temperatures cool. Early morning is a better option because it has slightly lower humidity and the body hasn’t had enough time to become fatigued by the heat.

Hydration is more than drinking water

Most people do not realise how much fluid they need during physical activities on a hot day. The general recommendation for hydration when exercising in hot weather is to drink 500 ml of water 1 hour before exercise, 150–200 ml every 15- 20 minutes during exercise, and 500 ml for every 0.5 kg of weight lost due to sweating (measure your weight before and after).

Pure water can help during exercises for less than an hour. Longer training requires replenishing electrolytes, especially sodium, potassium, and magnesium, which are lost through sweating. Oral Rehydration Solutions (ORS), coconut water, or electrolyte water with minimal amounts of sugar are possible alternatives. Refrain from caffeine intake before physical exercise, as it can increase dehydration.

Heat-adapted exercise

Lower the intensity by 20-30%. Opt to walk rather than run, and replace intense circuit-training exercises with yoga and other exercises in the shade. Limit workout time to 30-40 minutes and allow 10-14 days for acclimation. This process entails increased blood plasma volume, improved sweat efficiency, and a lower heart rate at the same workload.

Extremely hot weather does not mean that one cannot exercise. It just means that exercising without adequate precautions is very dangerous. With planned workouts, proper hydration, and reduced intensity, most people can continue working out outdoors during the summer months. Patients suffering from high blood pressure, diabetes, heart disease, and kidney problems need to talk to their doctor before engaging in exercise under extremely hot conditions. When it comes to extremely hot weather, discomfort is a message, not a sign of weakness.